In a reciprocative mechanical device such as a piston pump, fuel pump, solenoid and other actuator, linear motors and the like, typically there is a mass portion, that requires some form of suspension system to allow reciprocative motion relative to a base portion. Generally the suspension serves at least one of two primary functions; in the present invention the suspension system serves both of the following primary functions:
(1) in the absence of a sliding bearing system, to constrain the reciprocative motion of the mass portion to a straight line, with no canting, over a designated stroke length, and
(2) in the absence of external driving or restoring force, to act as a restoring force to return the mass portion to a desired quiescent location typically midway in the stroke length.
In the present field of endeavor directed to vibration control, both passive (inertial) and active (utilizing reciprocative drivers, typically electromagnetic), the evolution that has taken place in the ongoing search for satisfactory suspensions has included many different approaches including sliding bearings, flexure discs, flat springs, coil springs of both metallic and non-metallic resilient materials, each of which have been found to have disadvantages and shortcomings in this field of endeavor.
Flat spring flexures in the form of radial strips or circular diaphragms can offer simplicity, high ruggedness and reliability; however in simple “non-folded” deployment simply attached between a mass portion and a base portion, they cannot provide linear travel of one portion relative to the other unless made of elastic material, due to the geometric relationship of a right-angled triangle having the undeflected flexure length/radius as the X-axis base, and a half-stroke displacement as the Y-axis height: at stroke-end, the flexure has to actually “stretch” to at least the length of the hypotenuse.